Owners of sites containing soils contaminated with hazardous substances may be required by governmental or other regulations to remediate these materials. Examples of known methods of doing so include application of biological, physical or chemical methods to remove or stabilize/destroy the substances, or to transfer the contaminated material to approved off-site landfills. The methods used to remediate solid materials include bioremediation, aqueous soil washing including use of surfactants, soil extraction with organic solvents, thermal desorption and incineration. Although such methods may be effective, they also tend to be expensive.
There is substantial interest in development of cost effective methods for removing or remediating organic contaminants from solid particulate materials such as soil. Because of the low solubility of these organic contaminants in water, such contaminants tend to tightly adsorb on or absorb into the solid materials and consequently are less amenable to biodegradation by microorganisms, which normally requires an aqueous phase for growth and metabolism.
It has been observed that the degree of difficulty of extracting or remediating organic contaminants from soil increases with an increased content of clay and/or humic substances or organic carbon in the soil.
More economic methods for removal of hazardous contaminants from soils are required for purposes of remediating the soil and to prevent contaminants from spreading through the soil and/or to prevent contamination of groundwater.